As cellular phones and personal handy-phone systems become widely available, services provided to such telephones have been expanding beyond a telephone conversation. Among these additional services other than the telephone conversation service, character communication services (message services) are ones of the most popular services, and become generally recognized as a simple communication tool.
The message services are broadly divided into two categories; short massage services for communicating relatively short character massage between telephone terminals by specifying a telephone number of a destination terminal, and Internet mail services for communicating electronic mails over the Internet or other communication networks by specifying a mail address of a recipient of the mail.
As the number of users of the message services increases, a situation in which one wants to send the same message to a plurality of destinations increasingly occurs. In order to meet such demands, one of the short message services (a message broadcast service) allows the same message to be broadcasted to a plurality of destinations by registering groups of destinations in advance, and selecting a desired group or desired destinations in a group.
However, the conventional message broadcast service does not allow an Internet mail address to be included in the broadcast destinations. In addition, if a recipient of the broadcast message simply replies to the message, the reply message is sent only to the sender of the broadcast message and is not broadcasted to the other recipients of the broadcast message.
Therefore, the recipient of the broadcast message has to also utilize the message broadcast service, or send the same message repeatedly to a plurality of destinations. Even in such a case, however, if the recipient utilizes the message broadcast service when replying, since the destinations of the reply message does not always correspond to the destinations of the original broadcast message, the reply message may be sent to an irrelevant destination, or may not be sent to the destination to which the replay message has to be sent.
Furthermore, in this kind of message service, since there is not provided means for determining with reliability to whom the received message has been broadcasted, as well as whether the received message is a broadcast message or not, it is virtually impossible to send with reliability the reply message to the received broadcast message to the sender and other recipients of the broadcast message.